This invention relates generally to circuit testing devices, and more particularly concerns apparatus to test for voltages and electrical continuity. The invention enables the use of two tester probes to change from continuity testing to voltage testing, no switching devices being required and with the further advantage that no damage or injury can occur to the device or the user. In addition, the presence of 110 and 220 volts can be determined using a single probe, with sound or light indicators being activated, the use of a neutral or ground not being required. A sound indicator is usable to indicate continuity.
Electrical contractors and electricians must frequently determine whether or not voltage is present at a terminal, lead or line, as for example 110, 220 to 440 volts. If the outlet or terminal being tested is difficult to reach, the running of a separate ground line to accomplish the test becomes very difficult. Such workmen also frequently need to know if there is electrical continuity between two terminals; for example, if such continuity is lacking as between neutral and ground terminals at a receptacle, there is the possibility of a break in the neutral wire. Prior devices for resolving these questions have lacked the many unusual advantages in construction, mode of operation and results as are provided by the present invention.